Straining tank



1959 F. H. SCHWAIGER EI'AL 2,916,421

STRAINING TANK Filed March 28, 1958 3 Sheets-Sheet 1 AA 6 .By M, Zulu {MW 7 Ivar/ x5.

Dec- 8, 1959 F. H. SCHWAIGER EI'AL 2,916,421

' I STRAINING TANK 3 Sheets-Sheet 2 Filed March 28, 1958 3, mv a/ Dec. 8, 1959 F. H. SCHWAIGER EI'AI. 2,916,421

s'mmmc TANK Filed March 28, 1958 3 Sheets-Sheet 3 FIGA United States Patent 2,916,421 STRAINING TANK Frank H. Schwaiger and Robert C. Gadsby, St. Louis County, and Joseph Schwaiger, Afiton, Mo., assignors to Anheuser-Busch, Incorporated, St. Louis, Mo., a corporation of Missouri Application March 28, 1958, Serial No. 724,561 Claims. (Cl. 195-135) This .invention relates to a straining tank or grain extractor or lauter tub, and more particularly to a new type of straining tank for use in the brewing industry to remove extract from brewers grains.

At present, the conventional type lauter tub used in the brewing industry is relatively large and expensive. Many of these lauter tubs are from twelve to twenty-five :feet in diameter and have a relatively heavy and expen- ;sive power :driven ra'ke or lauter machine which rotates therein to agitate and loosen the grains. Typical devices of this sort :are shown in US. Patent Nos. 2,014,945 and 2,150,009 and others. Some breweries use a relatively large and expensive mash filter to remove the extract from the grains. Regardless of whether the conventional lauter tub with rotating blades therein or whether the :mash filter :is used, this step of the brewing process has in the past been the slowest and has been one of the governing steps in the production of beer. In other Words, in the usual brewing operation today, the-capacity of the equipment in this step of the brewing process largely determines the capacity of the brewery.

One of the principal objects of the present invention is to increase the efficiency of the extraction of soluble substances from material within a straining tank. Another object is to provide a'straining tank with the shortest exposure and contact time between the wort and grains and between thesparge water and the grains which have substances extracted therefrom, thereby extracting less of the undesired substances from the husks of the grains. This results in a cleaner and milder flavor for the resulting wort. Another object is to eliminate the mechanical agitator formerly required and avoid the formation of channels which the numerous knife .blades previously cut into the grain bed.

Another object of the present invention is to provide a straining tank which is relatively small and inexpensive compared to those lauter tubs and mash filters presently used to remove extracts from grains. Another object is to increase .the capacity for removing extracts from grains in a brewing operation, thereby increasing the capacity of the brewery. Another object is to provide a straining device which requires less time per batch and allows more brews per day. Another object is to provide for the fast removal of spent grains from a straining tank which can then be easily and rapidly cleaned.

Still another object is to provide a device which has a smaller initial cost and which requires fewer operators than previously required to etficiently operate a straining tank or mash filter.

These and other objects and advantages will become apparent hereinafter.

The invention is embodied in a straining tank having a conical bottom with an outlet therein, said tank having a multiplicity of draw-011 levels, each draw-off level having a plurality of draw-off pipes with relatively small openings therein, and means for controlling the flow from each of said draw-off levels. The invention is also em- 2,916,421 Patented Dec. 8, 11959.

ice

bodied in a method for drawing 011 the first wort in an upstanding tank through a multiplicity of draw-off levels positioned below the level of the grains, introducing water directly into the grains and drawing OK the Wort through said draw-oft levels and controlling the flow of the wort from each of said levels.

This invention also consists in the parts and in the arrangements and combinations of parts hereinafter described and claimed. In the accompanying drawings which form part of this specification and wherein like numerals and symbols refer to like parts wherever they occur:

Fig. l is a side elevational view of a straining tank or grain extractor or lauter tub embodying the present invention,

Fig. 2 is a side elevational view mostly in cross-section of the side opposite to that shown in Fig. 1,

Fig. 3 is a top plan view thereof,

Fig. 4 is a horizontal cross-sectional view taken along the line 4-4 of Fig. 1 but showing only the arrange- ,ment immediately below said line 4 4,

Fig. 5 is a horizontal cross-sectional view taken along :the line 5-5 of Fig. 1 showing within the tank only the Fig. 8,

Fig. 10 is an enlarged fragmentary view of a wort draw-01f pipe and support therefor, and

Fig. 11 is an enlarged fragmentary view of a protective slotted shield which allows liquid to pass into the vertical tubular sight glasses.

Referring now to the drawings in detail, it will be seen that the invention is embodied in a straining tank or grain extractor or lauter tub I having an elliptical head 2, a cylindrical shell 3, and a conical bottom 4. The head 2 is provided with manholes 5 with sliding covers 6-thereon and a centrally located vent pipe 7. The shell or wall 3 is provided with a manhole 8 and a suitable vertical sight glass 9 therein for viewing the contents. The conical bottom 4 has an outlet valve 10 at the very bottom, and an enlarged annular portion 11 having a conical screen 12 which is removable, forming a portion of said conical bottom 4 with an annular wort draw-01f chamber 13 therebetween. The bottom 4 is provided with an inlet pipe 14 with a valve 15 therein for controlling the flow of incoming mash or grain and water.

The cylindrical shell 3 is provided with a multiplicity of wort draw-01f levels L, as best shown in Figs. 4 and 5. A lower draw-olf arrangement is shown in Fig. 6. Each wort draw-off level L comprises a header 16 which extends diametrically across the tank 1. A plurality of draw-off pipes 17 extend horizontally from the header 16 on either side thereof in spaced relation. The pipes 17 are secured to the header 16 by suitable fittings 18 with their opposite ends '19 held at substantially the same horizontal level by means of supports 20 secured to the tank wall .3. Each support 20 has two fingers 21 extending upwardly in the shape of a V to act as a cradle for the pipe 17. The supports 20 also support a circular draw-off ring or pipe 22 which is spaced inwardly from the tank wall 3 but outwardly from the ends 19 of the pipes 17. The pipes 17 in the level shown in Fig. 4 are ofiset with respect to the pipes 17 in Fig. 5, so that in the eight upper draw-01f levels L, shown, the first, third, fifth and seventh levels 3 are like that shown in Fig. 5 and the second, fourth, sixth and eighth levels are like that shown in Fig. 4.

Pipes 23 and 24 are secured to the ends of the headers 16 and extend angularly toward each other to a central connection 25 to which is connected a water pipe 26 leading to a water header 27. The water pipe 26 has a suitable valve 28 therein. The central connection 25 also has a wort pipe 29 connected thereto which leads to a wort header 30. The wort pipe 29 has a suitable valve 31 therein.

The water header 27 is connected to a suitable source of water controlled by a valve 32 and extends upwardly to a suitable flushing ring 33 mounted in the elliptical head 2.

The wort header 30 has suitable piping 34 connected to the lower end thereof which leads to a conventional grant 35 having an outlet 36 therein for the desired wort and a recirculating outlet 37 for recirculating the wort if desired. A grant 35 is also provided with a drain 38. A suitable pipe 39 extends from said recirculating outlet 37 to a pump 40 which pumps the wort upwardly through a vertical pipe 41 having a valve 42 therein to a special side and flat discharge nozzle 43, best shown in Figs. 8 and 9, which discharges the recirculated wort against the inner surface of the tank wall 3 so as to minimize turbulence.

Each of the wort pipes 29 connected to a header 16 positioned within a particular level L is provided with a sampling line 44 having a valve 45 therein. Thesampling lines 44 each lead to a saccharometer 46 positioned on or near the grant 35. The sampling lines 44 are provided so that the total solids content of the wort taken olf at any particular level L can be accurately determined. The amount of wort taken from any level can be varied as desired by operating the wort valve 31 to either fully or partially open or close olf the draw-off system for a particular level. The saccharometers 46 are preferably Balling saccharometers or hydrometers or other devices which show directly the percentage of sugars, dextrins and other dissolved solids in the wort.

Each draw-0E pipe 17 is elongated and elliptical in shape as best shown in Fig. 10. The elliptical surfaces 47 and as well as the end surface 19 are provided with relatively narrow openings or slits 48. The openings or slits preferably are approximately /2 inch long and 0.025 inch wide although holes of the same width may be used if desired. The 0.025 inch dimension is critical for grains of the size normally used in a typical brewing operation and should not be increased even as much as 0.002 inch since such will allow undesired particles from the grains or husks to pass into the wort draw-off system thereby causing the wort to be cloudy or otherwise unsatisfactory. The openings 48 are positioned throughout the length of each of the pipes 17 and at the ends 19 thereof and completely around the periphery of the circular pipe 22 so that wort is drawn 0E substantially uniformly over the entire area of a particular level L. The space 49 between the edges of the staggered slots 48 in different rows is preferably about /a inch. The elliptical end 19 of each pipe is about 4% inches high and one inch wide. The pipes 17 are preferably about inches apart horizontally. The screen 12 is preferably a conical sheet which may be made in removable sections, having openings therein of the same dimensions as the slits or holes 48. The pipes 17 and 22 are preferably elliptical to prevent the accumulation of grains thereon as is the case with circular pipes on which grains tend to settle and accumulate to the point where the space between adjacent pipes may be bridged by the accumulation. The elliptical shape also aids in the removal of grains from the tank.

The center of each level L is spaced from the center of the level above or below a distance of 9 inches, which distance has been found to produce exception- .ally good results. Levels whose centers are spaced 12 inches apart do not produce results which are comparable to the 9 inch spacing, nor is it advantageous to have the levels substantially closer than 9 inches. This distance of about 9 inches is important, just as the 12 or 13 inch height in conventional lauter tubs is important, since heights greater than about 13 inches result in too much pressure or grains compacted too tightly so that too much suction must be used which in turn causes the grains to become pressed tighter against the screen.

The cylindrical shell 3 also has a shield 50 with slots 51 therein, as best shown in Fig. 11, to prevent grains from entering the space 52 between said shield 50 and said tank 3. A pipe 53 is connected to said space 52 and has a vertically extending tubular sight glass 54 extending upwardly therefrom. The height of the liquid in the sight glass 54 is the same as the liquid level within the tank. Another vertically extending tubular sight glass 55 is secured to the main wort collection header 30. The difference in the height of the liquids in sight glasses 54 and 55 is kept at a predetermined quantity to provide for more efficient operation. In effect, the difference in level indicates the rate at which the wort is being drawn oil. This difference can be controlled automatically if desired. Each of the sight glasses has a suitable small valve 56 at the bottom thereof to render it inoperative.

As best shown in Fig. 7, the portion of the inlet pipe 14 within the tank is elliptical and is provided with an elliptical discharge end portion 57 so as not to obstruct or collect grains on the top thereof when the grains are being removed. The tank shown in the drawings is about 9% feet in diameter with the top portion of the cylindrical shell 3 being about 16 feet vertically above the bottom of the conical bottom 4 and the bottom portion of the cylindrical shell 3 being about 4 feet vertically above said bottom, although these dimensions may be varied somewhat depending upon the capacity desired.

In operation, and with all of the tank surfaces and pipes clean and immaculate and all valves closed, the valve 15 is opened and mash or brewers grains with sufiicient water are pumped in through the inlet 14 at the bottom of the tank 1 until the top level of said mixture reaches about to the point 58 in the tank. The inlet valve 15 is then turned closed. After a proper rest period, the valves 31 of several or all levels are then opened and the wort is circulated through the grant 35 until clarity is reached. After the rest period, the first wort or wort initially extracted usually is not as clear as desired and is pumped back into the tank from the grant 35 through the pipes 39 and 41 to the nozzle 43, as shown in Figs. 1, 3, 8 and 9 against the side of the wall 3 so as not to disturb the grain and water in the lower portion of the tank. The wort from the tank is continuously circulated over the grant and back into the tank 1 until it runs clear. This usually takes about fifteen to twenty minutes. Thereafter, the wort is collected for use in the brewing operation.

The valve 60 is then opened so as to allow sparge water to enter the chamber 13 and pass through the screen 12 into tank and filter through the grains thereby removing the extract from the grains. The resulting wort is taken of]? uniformly at various levels through each of the wort draw-0E pipe levels L and through each of the pipes 17 and 22 and through the connections 23 and 24 and into the headers 16. If desired, the sparge water can be introduced through any of other levels within the tank and the wort removed from the remaining levels.

During the sparging operation, after the first wort is gone, the specific gravity of the wort of each of the pipe levels L is carefully watched and the wort valves 31 are used to control the amount of wort which is allowed to be taken off at any particular level. Of course, the small valves 45 in the sampling lines 44 are opened so that wort is allowed to pass through the sampling lines to the saccharometers 46 for each of the sampling lines. If desired, automatic ccontrols (not shown) may be includc d so that the saccharometers 46, or devices operatingibn similar or different bases, automatically open an! close the wort valves 31 so that each piping level L extracts a certain quantity of wort of certain desired characteristics.

During the extraction, it may become necessary to close the wort valves 31 of the lower pipe levels or of any other levels as the grains become spent. After sufficient wort has been extracted from a batch of grains and the grains become fully spent so that it is no longer desirable to make further extractions therefrom, the valve 60 is turned off so as to shut off the supply of incoming sparge water. The individual wort valves 31 are allowed to remain open until the wort from each draw-off level L reaches a predetermined value at which time that particular valve for said level is closed. After all of the valves 31 are closed, or even shortly prior thereto, the large outlet valve is opened and all of the grains with some amount of wort that remains fall through the opening 61 in the bottom of the tank.

With the outlet valve 10 still open, the tank 1 is flushed and cleaned. This is accomplished by opening the water valves 28 (with the wort valves 31 closed) and allowing water to surge through each of the draw-off pipe levels as well as through the top cleaning pipe 33 which is preferably circular with holes in the bottom portion thereof. Thus, all pipes are used to flush out the tank with water to remove all spent grains or portions thereof from the equipment. After this initial flushing, the sliding covers 6 on the top manholes 5 are opened and the tank is further flushed with hoses through the top manholes to make absolutely certain that all surfaces are absolutely clean.

The various pipe levels and surfaces and fittings can be inspected visually through the sight glasses 9, the top manholes 5, and the side manhole 8. After this, the manholes can be covered, the main outlet valve 10 closed, and the water valves 28 and draw-off valves 31 placed in their proper position. The inlet valve is then opened and another batch of mash or grains is allowed to enter into the straining tank and the operation previously described is repeated.

The invention is intended to cover all changes and modifications of the example of the invention herein chosen for purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention.

What is claimed is:

1. A straining tank having a tubular body portion and a conical bottom, said tank having an inlet in said conical bottom and an outlet at the bottom of said conical bottom, an inlet for directing water into said tank, said tank having a multiplicity of draw-off levels therein, each of said draw-off levels comprising a header with a plurality of draw-off pipes extending therefrom in spaced relation, said draw-off pipes being hollow and having relatively narrow slots therein, a pipe extending from each of said headers to a substantially vertical draw-off header, a valve in each of said pipes for controlling the flow of drawn off material therethrough, a connection to each of said draw-off levels with a valve therein, said connections being connected to a substantially vertical water pipe.

2. A straining tank comprising an upright tubular body portion with a conical bottom portion therebelow and a top portion thereabove, said conical bottom having an outlet therein for removing all of the material from the tank, means for directing water into said tank, a multiplicity of draw-off levels within said tank for drawing off liquid from within said tank at different levels, each of said draw-off levels comprising a header with a plurality of draw-off pipes extending therefrom, said drawoff pipes being hollow and having a plurality of slots 6 therein, a pipe extending from each of said headers to a main draw-off header positioned exteriorly of said tank, means for controlling the flow of material through said pipe, a water pipe connected to each of said headers within said tank, means for controlling the flow of material through said water pipe, and means connected to each of said draw-off levels for sampling the contents thereof.

3. A straining tank comprising an upright tubular body portion with a conical bottom portion therebelow and a top portion thereabove, said tank having a height greater than its width, said top portion having a vent therein, said conical bottom having an outlet therein for removing all of the material from the tank, means for directing Water into said tank, a multiplicity of draw-off levels within said tank for drawing off liquid from within said tank at different levels, each of said draw-off levels comprising a header with a plurality of draw-off pipes extending horizontally therefrom, said draw-01f pipes positioned in spaced relation and having a plurality of slots therein, a pipe extending from each of said headers to a main draw-off header positioned exteriorly of said tank, means for controlling the flow of material through said pipe, a water pipe connected to each of said headers within said tank, means for controlling the flow of material through said water pipe, and means connected to each of said draw-off levels for sampling the contents thereof.

4. A straining tank comprising an upright tubular body portion with a conical bottom portion therebelow and a top portion thereabove, said conical bottom portion having an inlet therein for receiving granular material and an outlet in the bottom thereof for removing said material, an inlet for directing water into said tank, a multiplicity of draw-0E levels in said tank for drawing ofi liquid from within the tank, said draw-off levels comprising a header with a plurality of draw-off pipes extending therefrom, said draw-off pipes being hollow and having a plurality of relatively small openings therein, a pipe extending from each of said headers to a substantially vertical draw-off header positioned exteriorly of said tank, said pipe having a valve therein for controlling the flow of material therethrough, a water pipe connected to each of the headers in said draw-off levels, said water pipes each having a valve therein to control the flow of water to said headers, and means connected to each of said draw-off levels for sampling the contents thereof.

5. A straining tank comprising an upright tubular body portion with a conical bottom portion therebelow and a top portion thereabove, said top portion having a vent therein, said conical bottom portion having an inlet therein for receiving grains and water and an outlet in the bottom thereof for removing said material, an inlet for directing water into said tank, a multiplicity of draw-off levels in said tank for drawing off wort from the tank, said draw-off levels comprising a header with a plurality of draw-off pipes extending horizontally therefrom, said draw-off pipes positioned in spaced relation and having a plurality of slots therein, a pipe extending from each of said headers to a substantially vertical draw-off header positioned exteriorly of said tank, said pipe having a valve therein for controlling the flow of material therethrough, a water pipe connected to each of said headers in said draw-off levels, said water pipes each having a valve therein to control the flow of water to said headers, means connected to each of said draw-off levels for sampling the contents thereof, and means connected to said tank for indicating the rate of flow from said tank.

References Cited in the file of this patent UNITED STATES PATENTS 804,979 Rach Nov. 21, 1905 1;272,458 Keller July 16, 1918 2,229,875 Schwartz et a1. Jan. 28, 1941 2,331,556 Lindgren Oct. 12, 1943 

1. A STRAINING TANK HAVING A TUBULAR BODY PORTION AND A CONICAL BOTTOM, SAID TANK HAVING AN INLET IN SAID CONI CAL BOTTOM AND AN OUTLET AT THE BOTTOM OF SAID CONICAL BOTTOM, AN INLET FOR DIRECTING WATER INTO SAID TANK, SAID TANK HAVING A MULTIPLICITY OF DRAW-OFF LEVELS THEREIN, EACH OF SAID DRAW-OFF LEVELS COMPRISING A HEADER WITH A PLURALITY OF DRAW-OFF PIPES EXTENDING THEREFROM IN SPACED RELATION, SAID DRAW-OFF PIPES BEING HOLLOW AND HAVING RELATIVELYY NARROW SLOTS THEREIN, A PIPE EXTENDING FROM EACH OF SAID HEADERS, TO A SUBSTANTIALLY VERTICALLY DRAW-OFF HEADER, A VALVE IN EACH OF SAID PIPES FOR CONTROLLING THE FLOW OF DRAWN OFF MATERIAL THERETHROUGH, A CONNECTION TO EACH OF SAID-OFF LEVELS WITH A VALVE THEREIN, SAID CONNECTIONS BEING CONNECTED TO A SUBSTANTIALLY VERTICAL WATER PIPE. 